Corrugated tubing



(No Model.)

. R. P. PRATT 8E C. D WAINWRIGHT- Y GORRUGATED TUBING. A No. 365,630; I Patented June 28, .1887.

FIGA. naga.

NA PETERS. PhnlLhugraphBr, Washingtov. l C.

,- VUNITED, STATES PATENT OFFICE.

RoNELLo E. PRATT, or REvERE, AND CHARLES D. WAI'NWRIGHT, or MED EoRD, MASSACHUSETTS, ASSIGNCRS To THE WAINWRIGHT MANUFAC- TURINC COMPANY, or PORTLAND, MAINE.

CORRUGATED TUBING.

SPECIFICATION forming part of Letters Patent No. 365,630l dated June 28, 1887.

-Application filed August 2; 1886.

To all whom, z''may concern:

:Be it known that we, RCNELLO'F. PRATT and CHARLES' D. `WAINWRIQHT, citizens of the United States, R. F. PRATT residing at Revere, Suffolk county, and C. D. WAIN- WRIGHT, at Medford, in the county of Mid# dlesex, both of theState of Massachusetts, have invented a new and useful Improvement in Corrugated Tubing, of which the following is lo a specification.

Our inventiou'relates to a peculiar construeA tion of corrugated tubing whereby we com,- bine great strength with very thin material.

Figures'l to.` 4 of the accompanying drawi 5 ings represent straight pieces of this improved wrought-metal tubing having different styles of corrugations. Fig. 5 represents a bent piece of this improved corrugated tubing. The principal use to which the spirally-cor- 2o rugated tubing is applied and for which it is especially adapted is in connection with feedwater heaters or condensers in which the water is made to passthrough the `tubes and is heated by exhaust-steam surrounding the tubing, or steam may pass through thetubing,

which is surrounded by water. The tubing is also used in expansion-joints, stean1 boilers, and in steam 'or hot-water radiators, and it is also applicable to various other uses 3o independently of its connection with Vfeed- Water heaters, condensers, expansioxrjoints, boilers, and radiators. n

In manufacturing spirally-corrugated tubing according to our invention We take either solid l 3 5 drawn seamless tube, brazed tube, lap or butt welded tube, composed of brass, copper, iron, steel, tin, lead, zinc, or any suitable metal, and corrugate it spirally with a single rib and groove from one end of the tube to the other 4ov similar tothe thread of a screw, which tube when so corrugated is very strong and rigid,and can consequently be made of very thin metal, thus admitting of the maximum amount of heat to be imparted to Water passing through the same from the surrounding steam, or vice versa. j f

To produce a spirally-corrugated wrought tube We take a plain Wroughtnxetal tube and place it upon a spirally-corrugated mandrel,

Serial No. 209,805. (No model.)

which is then placed between the centers of a 5o lathe, and a roll with annular corrugations is then forced onto the tube, so as to cause it to take the form of the corrugated mandrel, the annular corrugated roll being caused to travel from end to end ofthe tube by the spiral corruga- 5 5 tions on the mandrel. Vhen the tubehas been corrugated, the mandrel, with the tube up it, is removed from the lathe and the mandrel is rotated, which causes it to unscrew out of the tube. Another method of forming the cor- 6o rugations on the tube is to clutch a wrought metal tube in the head of the machine and Vinsert a short spirally-corrugated mandrel on the end of a rod that is free to travel (but not rotate) from end to end of the tube. annular corrugated roll is forced onto the tube, so as to cause it to take the form of the corrugated mandrel. This roll is caused to travel from end to end of the tube by the screw-feed of the machine,while the short mandrel is 7o caused to travel inside by the corrugations formed on the tube. The tubing is capable of Ybeing bent to any degree of curvature, as exemplified in Fig. 5, and this Without straining or injuring the outer portion' of curved 75 part, the double archesforming braces of great rstrength. A longitudinal section of the tube showsjthe metal in a continuous siuuous curve longitudinally of the tube Without angles;

As thus constructed it is stronger than a tube 8o with angular corrugations, and can be more easily bent without liability of breakage. The expansion and contraction ofthe tubing, due

to changes of temperature, take place in the body of the tubing, and consequently do not affeet thejoints of the same.

By reason of the peculiar form of the tubing any scaleformed Within or without the same is readily thrown off.

That We claim as our invention, and desire 9o to secure by Letters Patent, is

. f l. Awrought-metal tube having spiral corrugations, composed of a .continuous spiral rounded external rib and a continuous spiral rounded groove between the coils of said rib, the metal being in a continuous sinuous curve longitudinally of the tube, substantially as described.

An 65V 2. The process of forming spirally-corru names to this specification in the presence of gated Wrought-metal tubes, which consists, two subscribing witnesses. rst, 1n placing a plain wrought-metal Lube on a RONELLO F. PRATT splrally-corrugated mandrel, then rolling the T 5 metal of the tube into the corrugations of the CHARLES D' XVAIN RIGHT' mandrel, and then unscrewing the mandrel Vitncsses: from the tube, substantially as described. J. H. ADAMS, In testimony whereof we have signed our E. PLANTA. 

